This invention relates to improvements in gravity operated fluid flow systems designed to assure the presence of an adequate level of a fluid in a sump, such as a desired level of oil in the crankcase of an internal combustion engine.
U.S. Pat. No. 3,777,852 entitled "Automatic Oil Level Regulator" and assigned to the parent company of the assignee of this invention shows a prior art system having a reservoir of which the inventive features of this disclosure constitute an improvement.
Gravity flow oil level regulators generally consist of an air tight reservoir for containing a supply of oil, a supply conduit for conducting oil from the reservoir to the engine crankcase and an air carrying sensing conduit having an end located at the desired oil level in the crankcase and another end located above the level of oil in the reservoir. The reservoir must be positioned at a higher level than the crankcase to provide gravity induced fluid flow from the reservoir to the crankcase.
At its desired level in the crankcase, oil seals the end of the sensing conduit in the crankcase. When the oil falls below the desired level the end of the sensing conduit is no longer sealed and air passes through the conduit to an air chamber or ullage above the oil level in the reservoir.
The air flow through the sensing conduit relieves a partial vacuum induced in the reservoir air chamber by gravitational forces acting on the oil in the supply conduit. Consequently, oil flows downwardly through the supply conduit and into the crankcase until the end of the sensing conduit in the crankcase is once again covered by oil, which prevents air from entering the line. Oil flow continues until a partial vacuum is again formed in the air chamber above the oil in the reservoir. Flow through the supply line ceases when the force of the partial vacuum above the oil level in the reservoir equals the gravitational forces inducing the oil to flow downwardly through the oil supply conduit.
When the oil level in the crankcase again falls below or unseals that end of the sensing conduit which is in the crankcase the above cycle will be repeated.